-- State Monad for the Yhc Core Erlang Backend.


module Yhc.Core.BackEnd.Erlang.EGMonad (
  EG (..),
  EGM,
  getCnt,
  storeCVar,
  checkCVar,
  currFName,
  module Control.Monad.State)
where

import Data.Maybe
import Yhc.Core.Extra
import qualified Data.Map as M
import qualified Data.Set as S
import Control.Monad
import Control.Monad.State


data EG = EG {
   stateCnt :: Int                                -- counter to generate unique names
  ,currFun :: CoreFunc                            -- current function being compiled
  ,caseVars :: S.Set CoreVarName                  -- set of case variable names
  ,funcMap :: M.Map CoreFuncName CoreFuncName     -- map of function names (Yhc -> Erlang)
  ,strctMap :: M.Map CoreFuncName [Bool]          -- strictness map
  ,expFunc :: [CoreFuncName]                      -- list of exported functions
  ,coreRef :: Core                                -- reference to core
  ,coreAnno :: CoreAnnotations                    -- annotations for this core
  ,emodName :: String                             -- Erlang module name
}               
                
getCnt :: EGM Int
                
getCnt = do     
  c <- gets stateCnt
  st <- get       
  put st {stateCnt = c + 1}
  return c

type EGM a = State EG a

currFName :: EGM CoreFuncName

currFName = gets currFun >>= return . coreFuncName

storeCVar :: CoreVarName -> EGM ()

storeCVar cvn = do
  cfn <- currFName
  cvset <- gets caseVars
  let fvn = cfn ++ "::" ++ cvn
  st <- get
  put st {caseVars = fvn `S.insert` cvset}
  
checkCVar :: CoreVarName -> EGM Bool

checkCVar cvn = do
  cfn <- currFName
  cvset <- gets caseVars
  let fvn = cfn ++ "::" ++ cvn
  return $ S.member fvn cvset